The Translocation of Two Organic Arsenicals in Purple Nutsedge

Abstract

The translocation of disodium methanearsonate (DSMA) and amine methanearsonate (hereinafter referred to as AMA) in purple nutsedge (Cyperus rotundus L.) was studied following foliar applications. Tracer techniques with DSMA-14C and chemical analyses for elemental arsenic (hereinafter referred to as As) suggested apoplastic and symplastic movement of both arsenicals. Chromatographic studies of extracts from DSMA-14C-treated plants indicated that the compound was not readily broken down. The carbon-arsenic bond appeared to remain largely intact, although some 14C activity was found in respiratory CO2 several days after treatment. A comparison between the Rf value of the radioactive plant extract to that of standard DSMA-14C suggested that a plant extract-DSMA complex may have been formed. Over 85% of the material applied to the plant remained in the treated shoots. DSMA moved in both acropetal and basipetal directions, and such movement within a single leaf was not influenced by relative leaf age. The arsenicals were not redistributed in the shoot or in the tuber system, but As was accumulated in terminal tubers following repeated applications.